Device for cleaning internal tubular surface



M. D. BERRY 3,124,820

DEVICE FOR CLEANING INTERNAL TUBULAR SURFACE March 17, 1964 Filed Feb. 20, 1963 INVENTOR Mn m/D. 3500/ a (4 ifldllfg/ United States Patent Oil ice 3,124,820 Patented .Mar. 17, 1 964 3,124,820 DEVICE Fflll CLEANING INTERNAL TUBULAR SURFACE Melvin 1). Berry, Marion, Ind., assignor to Radio Corporation of America, a corporation of Delaware Filed Feb. 20, 1963, Ser. No. 259,929 4 Claims. (Cl. 15-10409) This invention relates to apparatus for cleaning internal tubular surfaces, and particularly, though not exclusively, to the cleaning of the internal surfaces of tubular necks of cathode ray tube bulbs.

-In present day manufacturing practices, the internal neck surface of a cathode ray tube bulb is cleaned after a phosphor screen and a conductive coating are applied to internal portions of the bulb. One suitable apparatus for per-forming this cleaning operation comprises a rubber auger for squeezeeing the neck of the bulb after it has been flushed successively, for example, with acid and with water. One problem encountered in this cleaning operation is that prior art rubber angers are adapted for use with only one diameter neck size, whereas in normal manufacturing processes different size bulbs are intermixed as they pass along the assembly line at a neck cleaning station.

It is therefore an object of this invention to provide an improved auger squeegee which can be used with a plurality of different size bulb necks.

In one example of the invention, an auger comprises a ribbon-like rubber squeegee blade which has one or more longitudinal wiping grooves adjacent to one of the blade edges in one of its flat surfaces and a folding groove substantially opposite the wiping groove in the opposite flat surface. The blade is twisted about its longitudinal axis to form a helix similar to a wood auger. be clamped between a pair of similarly twisted stiff metal straps.

In the drawings:

FIG. 1 is a side elevation view of an auger which embodies the invention;

FlG. 2 is a side elevation view of the auger of FIG. 1 prior to its being twisted into its helical shape;

FIG. 3 is a section taken along line 33 of FIG. 2;

'FIG. 4 is a section view of the auger of FIG. 1 in neckcleaning relationship within the neck of a cathode ray tube bulb; and

FIG. 5 is a section similar to that of F IG. 4 illustrating the neck-cleaning relationship of the anger of FIG. 1 in a bulb neck having a smaller diameter than the bulb neck of FIG. 4.

Referring now to FIG. 1, an anger is shown which comprises a ribbon-like squeegee blade 16 of gum rubber or other suitable resilient material which is provided with an array of longitudinal grooves as hereinafter described in greater detail with reference to FIGS. 2 and 3. The grooved blade 16 is twisted into a helical shape and clamped between a pair of similarly twisted stiff metal straps 18 which extend longitudinally along the grooved blade 16. The straps 1-8 are ioined together at their adjacent ends, and one pair of their ends is secured to a cylindrical base 21) provided with a pair of lugs 22. The cylindrical base 20 and lugs 22 'form a bayonet-type fitting for receipt into a rotatable socket (-not shown) for supporting and rotatably driving the auger 10.

FIGS. 2 and 3 illustrate the assembled elements of the auger It), as described with reference to FIG. 1, but prior to the twisting of the auger into its helical shape. The blade 16 includes two flat surfaces 24 and 26, each of which is provided with a pair of parallel longitudinal wiping grooves 28 and 3t} and a folding groove 32. The two pairs of wiping grooves 28 and 3d are disposed ad- The blade may jacent to different longitudinal edges of the blade 16. Each of the two fold-ing grooves 32 is associated with a different pair of the wiping grooves and is disposed substantially opposite its associated wiping igrooves on the opposite flat surface of the blade therefrom. Each folding groove 32 is preferably slightly radially offset relative to either of its associated wiping grooves 28 or 30 from the longitudinal axis of the blade 16. This offset serves to produce a preferred flexing of the blade 16 in its neckcleaning relationship with a tubular surface as illustrated in FIGS. 4 and 5.

The pair of metal straps 18, considerably narrower than the rubber blade 16, cover only the central longitudinal portion of the blade 16. The grooved portions of the blade 16 are thereby exposed so that edges of the wiping grooves 2i and 30' may produce a squeegeeing action when the auger is disposed in neck-cleaning relationship with a cathode ray tube bulb neck.

In order to facilitate insertion of the auger 10 into the bulb neck 12, the leading end 34 of the grooved blade 16 is tapered. The degree of the taper is such that when the grooved blade 16 is twisted into its helical shape and flexed for insertion into the neck 12, the edges of the end 34 will lie substantially in a plane perpendicular to the axis of the auger 1ft.

FIG. 4 illustrates the auger 10 in neck-cleaning relationship within a relatively large diameter cathode ray tube neck 12. In the large-sized neck 12, the grooved blade 16 of the auger flexes into a shallow S-shape such that the trailing edges 35 of the two outer wiping grooves 28 contact the internal surface of the neck 12 to perform the desired squeegee action. The two folding grooves 32 of the blade 16 are compressed slightly toward a closed or folded condition in formation of the shallow S-shape of the auger.

FIG. 5 is a view similar to that of FIG. 4 but illustrating the auger 10 in a cathode ray tube bulb neck 36 whose diameter is smaller than that of the neck 12. When the auger 10 is inserted into the small neck 36, the grooved blade 16 is flexed into an extreme S-shape. The trailing edges 35 of both the outer wiping grooves 28 and the inner wiping grooves 30' contact the internal wall 36 and perform the desired squeegee action. The two folding grooves 32 are substantially, completely closed or folded upon themselves when the grooved blade 16 is flexed into the extreme S-shape in a neck-cleaning operation in the small neck 36.

In prior art angers not provided with the folding grooves 32, it is very diflicult, if not impossible, to insert the auger into a small neck such as the neck 36. The folding grooves 32 permit the flexing of the grooved blade 16 to the extreme S-shape so that insertion into a small neck is facilitated. Furthermore, in prior art angers which do not have the wiping grooves 28- and 30, a bulb neckespecially a small bulb neck-4s contacted by a portion of the flat side of the auger blade 16 instead of by one or more edges such as are provided by the grooves 28 and 30. Where such flat-surface contact occurs, an ineffective squeegee action results. Thus, as compared with prior art angers, the auger 10 not only permits its use in both large and small size necks, but also provides edges which produce a superior squeegee action as compared to that provided by prior art angers.

The auger blade 16 may be made from any suitable material which may be suitably grooved and which will provide a suitable squeegeeing action. The metal straps 18 may be made from any suitable material which can be suitably twisted into the desired helical shape and which will retain that shape. Gum rubber and stainless steel have been found to be preferred materials for the blade 16 and straps 18, respectively.

Furthermore, it is within the scope of the invention to provide the grooved helical squeegee blade 16' as a selfsupporting element and thereby dispense with the metal support straps 1 8.

In one example of this invention, the auger 10 is designed to be used on industry-standard bulb necks of 1%; inch external diameter (0.955 inch internal diameter) and 1%; inch external diameter (1.238 inches internal diameter). The grooved blade 16 is composed of pure gum rubber 5 inch thick by 1% inches wide by 4% inches long and having a durometer hardness of between 30 and 40. Each of the grooves 28 and 30 and 32 is semi-cylindrical with a diameter of %2 inch. The spacing between adjacent edges of the wiping grooves 28 and 30 is inch and the outer edge of the outer wiping groove 23 is spac d inch from the longitudinal edge of the blade 16. Each of the folding grooves 32 is centered opposite its associated pair of wiping grooves 28 and 30. The tapered ends 34 of the blade 16 are provided by chamfering the leading corners of the blade A; inch back along the longitudinal edge and inch in toward the central axis of the blade. The metal straps 18 comprise two inch thick by inch wide stainless steel strips welded together at each end. The metal straps 18 and grooved blade .16 are twisted one complete turn to provide the desired helical shape.

What is claimed is:

1. Apparatus for cleaning internal tubular surfaces comprising a ribbon-like squeegee blade twisted about its longitudinal axis into a helical auger-like form, said squeegee blade having adjacent a longitudinal edge thereof a longitudinal wiping groove in one of its fiat surfaces and a longitudinal folding groove radially offset relative to said wiping groove in the other of its flat surfaces.

2. Apparatus for cleaning internal tubular surfaces comprising:

(a) a ribbon-like squeegee blade having adjacent a longitudinal edge thereof a pair of parallel longitudinal wiping grooves in one of its flat surfaces and a longitudinal folding groove substantially opposite said wiping grooves in the other of its flat surfaces, said squeegee blade being twisted about its 4 longitudinal axis into a helical auger-like form, and (b) means for maintaining said squeegee blade in said twisted helical shape. 3. Apparatus for cleaning internal tubular surfaces 5 comprising:

(a) a ribbon-like squeegee blade having adjacent a longitudinal edge thereof a pair of parallel longitudinal wiping grooves in one of its flat surfaces and a longitudinal folding groove substantially opposite said wiping grooves in the other of its flat surfaces, said squeegee blade being twisted about its longitudinal axis into a helical auger-like form,

(1)) a pair of parallel stiff metal straps disposed parallel to said blade with said blade being sandwiched therebet-ween, said pair of straps being secured to gether at their adjacent ends and being twisted about their central longitudinal axis into a helical form similar to that of said squeegee blade, whereby said blade is maintained in its helical form, and

(c) means attached to said metal strap for mounting said apparatus on a rotatable drive means.

4. Auger-like squeegee apparatus comprising:

(a) a ribbon-like squeegee blade twisted about its longitudinal axis into a helical form, said blade having adjacent one of its longitudinal edges a first pair of longitudinal wiping grooves in one of its fiat surfaces and a first folding groove substantially opposite said first pair of wiping grooves in the other of its flat surfaces, said blade also having adjacent the other of its longitudinal edges, a second pair of longitudinal wiping grooves in said other fiat surface and a second folding groove substantially opposite said second pair of wiping grooves in said one flat surface, and

(b) a pair of twisted stiff metal straps disposed one on each side of said blade and parallel therewith to maintain said blade in its helical form.

References Cited in the file of this patent UNITED STATES PATENTS 2,313,042 Bay Mar. 9, 1943 

1. APPARATUS FOR CLEANING INTERNAL TUBULAR SURFACES COMPRISING A RIBBON-LIKE SQUEEGEE BLADE TWISTED ABOUT ITS LONGITUDINAL AXIS INTO A HELICAL AUGER-LIKE FORM, SAID SQUEEGEE BLADE HAVING ADJACENT A LONGITUDINAL EDGE THEREOF A LONGITUDINAL WIPING GROOVE IN ONE OF ITS FLAT SURFACES AND A LONGITUDINAL FOLDING GROOVE RADIALLY OFFSET RELATIVE TO SAID WIPING GROOE IN THE OTHER OF ITS FLAT SURFACES. 